The present invention relates to disposable filter cartridges and more specifically to a disposable filter cartridge having an improved end cap.
Filters are widely used to remove contaminates from the oil that is used to lubricate machinery such as internal combustion engines, hydraulic equipment, etc and additionally, for filtering other liquids. An filter typically includes a filter housing and a filter cartridge that is mountable in or to the housing. Typical oil filters in automotive applications are changed every several thousand miles and few of those filters are reusable. Consequently, large numbers of oil filters are disposed annually creating a significant environmental issue with respect to the used filters.
For many years filter cartridges employed metal structural members or housings to achieve the rigidity needed to prevent the filter from being crushed due to the internal pressures experienced by the filter. Filters have typically been produced as either cartridge type filters or spin-on filters.
Cartridge type filters employ a filter cartridge that is disposed within a filter housing. Cartridge type filters have have provided with metallic structural members that support a paper filter element. The use of such metallic structural members is typically undesirable due to the post removal pocessing complexities and costs associated with such cartridges.
Spin-on filters in metallic cans became popular due to the ease of replacement of such filters. The use of spin-on filters has become undesirable due to the disposal problems presented since such filters contain metal components as well as filtration elements having residues that may require post removal processing prior to disposal.
More recently, efforts have been made to develop what has been referred to as an environmentally friendly filter cartridge that is mountable within a housing and is fabricated solely of plastic supporting members and a paper filter element. Such a filter cartridge may be crushed prior to disposal and/or burned. Examples of disposable oil filter cartridges are disclosed in U.S. Pat. Nos. 5,685,985 and 5,702,602.
Conventional non-metallic filter cartridges include a generally cylindrical paper pleated filter member having a through bore. First and second end caps are bonded to opposing ends of the filter member. An opening is provided in each of the end caps. The opening in one of the end caps is sized to receive an inlet tube. To mount the cartridge, the cartridge is positioned in a mounting position such that the inlet tube extends through the opening in the first end cap. A fluid seal is provided between the inner surface of the first end cap opening and the inlet tube. Consequently a liquid pumped into the disposable filter must pass through the pleated filter member prior to exiting the filter housing and particles flowing through the filter are trapped within the filter member.
A known disposable filter cartridge includes a felt gasket that is thermally bonded at the periphery of an opening in the end cap. The need to thermally bond the felt gasket to the end cap to maintain the gasket in position adds complexity and cost to the manufacturing process. Accordingly, it would be desirable to have an end cap design for a filter cartridge that provides an effective seal and that can be manufactured in high volume for low cost.